Eitan Bluman shows off some math skills:

Mathematical addition and subtraction can be performed between two datetime data types:

`SET`

`@d2 = '1900-03-30 18:00'SELECT@d1 + @d2 -- result: 1900-04-01 10:15:15.900, @d1 - @d2 -- result: 1899-10-05 22:15:15.900, @d2 - @d1 -- result: 1900-03-29 01:44:44.100`

This means that we can have basic

datetime arithmeticsin SQL server. We can use subtraction tofind an accurate difference between two dates, and use addition toadd an accurate interval to a datetime column or variable.

This is one of those things you can do, but I’m not very fond of. First of all, as Eitan points out, you can’t do these in the (in all ways superior) DATETIME2 data type. Secondly, it adds some confusion to the code, as you don’t always get what you expect.